VoIP/(802.11g) ADSL2+ (VPN) Firewall Router
Chapter 4: Configuration
PSTN Auto-fallback: Whenever VoIP SIP responses error and error code matching with the codes in the
Edit section, the VoiP calls will automatically fallback to PSTN. In the other word, the call will be called
via the PSTN when VoIP SIP returns an error code.
Click the Edit to add or remove the responses code. To be sure the code is separated by a comma(,).
For more information about SIP responses codes, please check to link to
http://voip-info.org/wiki/view/sip+response+codes where you can get to know the meaning of each error
Advanced – PSTN Environment Adjustment
PSTN Environment Adjustment options will help you to adjust the onhook and offhook voltage detection
values for your environment. You should use these if the default values are incorrect and result in PSTN
calls not being detected properly, e.g. calls being terminated within 5 seconds of being answered. The
actual levels are determined by your environment including the number and type of telephones used.
Note: ONHOOK means hung up.
To take your phone OFFHOOK, lift the receiver then press Hook/Flash until you hear your normal PSTN
dialtone, not your VoIP dialtone. Wait several seconds and then press Check Level.
You should check the OFFHOOK value for each telephone you have connected to this device. Set the
OFFHOOK voltage to the lowest setting registered for all your telephones, e.g. if your telephones return
values of 4, 5 and 7 then you should set your OFFHOOK voltage to 4.
Note: The detected values will not automatically be set by the Check Level function; you must enter the lowest level
detected after testing all your telephones.